When he was in his teens, his father introduced him to the local Masonic Lodge. As an adult, he joined the Jennings-Bankhurst expedition, which was looking for the Ark of the Covenant. The Ark was acquired by Gebmoses III, and Marillian tracked the Ark to Kampuchea. Gebmoses caught and killed him in front of the Ark, which resurrected him. He then swore eternal loyalty to Gebmoses.
Near the end of the 26th century, he met Bernice Summerfield. Since she needed a childbirth license to continue her research, she agreed to marry Marillion, thus gaining access to the British Library and other forbidden books.